A variety of surgical instruments are employed in various open, endoscopic, and laparoscopic surgeries. One group of such instruments is utilized to manipulate tissue, seal or staple tissue, and/or transect tissue. These instruments can include a distal end effector having opposed jaw members that move relative to one another to grasp tissue therebetween. Certain of these instruments can also include a cutting mechanism that can be advanced through the grasped tissue to transect it. Electrical or other energy can also be delivered to the grasped tissue to seal the tissue prior to, or concurrent with, transection. For example, electrical energy can be applied to the grasped tissue by various mono-polar and bi-polar radio frequency (RF) electrodes or other energy delivery structures coupled to the jaw members.
These surgical instruments often include a proximal actuator portion from which the distal end effector can be controlled. The proximal actuator portion can include a plurality of triggers or other control mechanisms to control the various functions of the instrument. For example, a first trigger can control the opening or closing of the jaw members to grasp tissue, while a second trigger can control the operation of a cutting mechanism and/or the delivery of energy to seal tissue. In use, a user can actuate the first trigger and latch it in an actuated or closed position to securely grasp and compress tissue between the first and second jaw members, then the user can actuate the second trigger to transect and/or seal the tissue.
The separate control triggers or other control mechanisms of the instrument can be susceptible to user error, however. For example, a user might actuate the second trigger (e.g., to transect and/or seal tissue) before fully actuating and/or latching the first trigger (e.g., to securely clamp tissue between the jaw members). Alternatively, a user might inadvertently release the first trigger while the second trigger is still being actuated, thereby releasing the grasped tissue as it is being transected and/or sealed. These actions can result in an incomplete or non-existent tissue seal and/or transection. This is because sufficient compression is important to both forming a good seal and facilitating passage of the cutting mechanism through the tissue.
Accordingly, there is a need for surgical instruments that include a trigger lockout feature to prevent actuation of a first trigger until such time as a second trigger is properly actuated. There is also a need for surgical instruments that prevent the release of an actuated first trigger until such time as the second trigger is fully released.